Hydraulically balanced tracer with eccentrically mounted tracer arm



Dec. 23, 1952' Filed June 9, 1949 G. HUMES 2,622,616 HYDRAULICALLYBALANCED TRACER WITH ECCENTRICALLY MOUNTED TRACER ARM 3 Sheets-Sheet lINVENTOR. GALE HUMES.

ATToRNE).

Dec, 23, 1952 G. HUMES 2,622,616

HYDRAULICALLY BALANCED TRACER wrra ECCENTRICALLY MOU ARM NIIED TRACER 3Sheets-Sheet 2 Filed June 9, 1949 INVENTOR. GALE HUMESA.

BY 1 fianr I A ATToRNEY.

Dec. 23, 1-952 .HUMES 2,622,616 HYDRA CA Y BALANCED/TRACER H TED 5Sheets-Sheet 3 ECCE'N. IGALLY MOUN TRACER Filed June 9, 1949 W la I 6 aIQEH Ii /////4 mm 01144) E9- 8 1 1i 5/. 9 ATTORNE).

Patented Dec. 23, 1952 HYDRAULICALLY BALANCED TRACER WITH ECCENTRICALLYMOUNTED TRACER ARM Gale Humes, Garden City, Mich, assignor to ManuelTurchan, Dearborn, Mich.

Application June 9, 1949, Serial No. 98,016

(Cl. l37619) 4 Claims.

This invention relates to tracers, and more particularly to thehydraulic tracer used in conjunction with reproducing devices andmachines which employ the use of a pattern which is sought to beduplicated by the cutting tool, with the tracer contacting the surfaceof the pattern and by its movements in traversing the same controllingthe hydraulic valve within the tracer, which in turn controls the flowof pressure fluid to one end or the other of a hydraulic cylinder, withsaid cylinder in turn governing the feed movement of the cutting toolwith respect to a work piece.

Heretofore in tracer controlled reproducing devices of this type asource of pressure fluid is delivered to the tracer housing and by thepositioning of the valve element therein is directed to one end or theother of the hydraulic cylinder which controls the relative feedmovement of the cutter with respect to the work, or the relative feedmovement of the work with respect to the cutter.

It is the principal object herein to provide an improved tracerconstruction for more facilely responding to the surface of the patternto thereby more accurately reproduce from the pattern an identical copythereof in the work piece.

It is the further object of this invention to provide an improved tracervalve as well as an improved tracer valve sleeve construction.

It is the further object of this invention to provide an improved andnovel mounting of the tracer tip upon the end of the tracer spindle.

These and many other objects will be seen from the followingspecification and claims in conjunction with the appended drawings inwhich: I

Figure 1 is an elevational section of the complete tracer constructionwith the tracer spindle partially broken away.

Figure 2 is an elevational section of the improved tracer sleeve.

Figure 3 is an elevational line 3--3 of Fig. 2.

Figure 4 is an elevational line 44 of Fig. 2.

Figure 5 is an elevational line 55 of Fig. 2.

Figure 6 is an elevational line 6-6 of Fig. 2.

Figure 7 is an elevational line 7-7 of Fig. 2.

Figure 8 is a fragmentary elevational section taken on line 88 of Fig.7; and

section taken on section taken on section taken on section taken onsection taken on Figure 9 is a fragmentary elevational section taken online 9-9 of Figure 8.

Fig. 10 is a fragmentary side elevational view of the tracerillustrating the arrangement of its fluid ports.

It will be understood that the above drawings illustrate merely apreferred embodiment of the present invention and that other embodimentsof equivalent structures are contemplated within the scope of the claimshereafter set out.

Referring to Figure 1 the hydraulic tracer includes the hollowcylindrical body I l within which is a press-fit sleeve 12 having at itslower end depending threaded flange I 3. Hollow cylindrical barrel i4 isthreadably joined at its upper end to the flange l3 and dependsdownwardly therefrom with its lower end interiorly threaded at l5.

The adjusting nut I6 is positioned within the lower end of barrel l4engaging the threads l5 and is secured in the desired adjusted positionby lock nut l1.

Annular bearing [8 is press-fit on tracer spindle 2! while thecorresponding bearing race I9 is supported within the barrel l4 upon theadjusting nut 16, there being a plurality of ball bearings or balls 20employed. It will be noted that the interior upper portion of the raceI9 is cone shaped or inclined at point 2|, and in the operation of thetracer mechanism any lateral thrust upon the tracer tip 26 will projectsome of said balls against said upwardly and outwardly divergingsidewalls 2|. Consequently it is apparent that the lateral thrust of apattern upon the tracer tip 26 will effect a corresponding upwardmovement of the tracer spindle 2| to control the tracer valve in aconventional manner.

The lower end of the tracer has mounted thereon a tracer tip adapter 22secured by the lock nut 23. Tracer arm 24 is secured to and projectsdownwardly from said adapter being eccentrically arranged out ofalignment with the longitudinal axis of tracer spindle 2|. Arm 24 has atransverse slot adjacent its lower end to receive tracer tip 26 whichmay be adjustably secured therein by the set screw 21. This is importantas it is possible by this construction to arrange the pattern engagingtip of the tracer in alignment with the spindle axis, or on the as toobtain a lead, or on the other hand, could be arranged if desired uponthe other side of the spindle axis.

The pattern 26 is fragmentarily shown with the tracer tip merely incontact engagement therewith so that the tracer valve 38 will be in aneutral position, and there will be no flow of pressure fluid throughthe tracer valve, or out either of the delivery channels 62 or 65hereafter described.

Annular cup shaped guard 28 with a diameter in excess of the exteriordiameter of barrel I4 is secured to the lower end of spindle 2iintermediate the latter and the adapter 22, with a portion of said guardextending upwardly around the lower end of said barrel. As said guard issecured to the spindle 2|, it is apparent that its accidental engagementwith a part of the reproducing machine, or for that matter itsaccidental engagement with any object will in effect transmit a lateralthrust to the lower end of spindle 2|, and by virtue of the balls 23said lateral thrust will be transmitted to a L slight upward movement ofsaid spindle causing the tracer valve which is mounted thereon to effectan outward feed movement of the support upon which the tracer is mounteduntil the lateral thrust is removed from said guard.

Spindle 2| has a transverse guide slot 29 formed therein to receivetransverse stabilizer pin 39, the annular eccentric ends 3i of which arejournalled and supported within ball bearings 32, secured withincorresponding slots formed within barrel l4. Suitable plugs 33 areemployed to cover said slots after said pin is properly positioned. Inview of the eccentric mounting of pin 30, the latter acts as a means toprevent rotation of spindle 2i, and at the same time there is sufiicientclearance between said stabilizer and the interior vertical walls ofslot 29 so that there is a slight guiding relation between saidstabilizer and said spindle. It will be noted that the axis of thestabilizer is parallel to the longitudinal axis of tracer tip 26 so thatsaid stabilizer will not interfere with the normal operation thereof.

Conical central recess 34 is formed in the upper end of spindle 2| tocooperatively receive the ball 36, there being a transverse slot 35formed adjacent the upper end of said spindle with its interior portionin communication with the lower end of the conical recess 34.

Tracer valve 38 is centrally arranged within the tracer body and isslidably positioned within sleeve l2 with a slip fit, but with no moreclearance than is necessary to provide for a freely movable valve withinsaid sleeve. The lower end of said valve has a corresponding conicalcentral recess 31 at its lower end which cooperatively receives andengages a portion of the preferably metallic ball 36, whereby any upwardaxial movement of said spindle will be simultaneously transmitted tovalve 38, and furthermore any downward movement of said spindle willpermit downward movement of the valve 33 under the action of coil spring4|.

Top cap 39 has an annular portion which is projected down into the bodyI I, while the depending portion of said cap is threaded into the upperend of the sleeve I2. Central downwardly depending sleeve 40 forms apart of said cap, and a coil spring is loosely arranged around saidsleeve with its lower end engaging valve 38, and with its upper endbearing against the bearing 42 within the upper portion of cap 35. Thusif for any reason the valve stem 43 should be manually rotated the coilspring is free to rotate therewith so that there will be no change inthe relationship of the spring to the valve.

It is contemplated that the cap 39 is rotatably adjustable forregulating the tension in the spring 4| which in turn regulates itsdownward pressure upon the valve 38.

Central stem 43 is threaded at its lower end within a correspondingcentral threaded opening in the upper end of said valve, said stem beingloosely projected upwardly through the sleeve 43, and with an adjustingdisc 44 being mounted upon the upper end of said stem and securedthereto by the lock nut 45.

It is apparent that the stem as well as the disc as will permit manualadjustments upwardly or downwardly of the valve 38, however means forefiecting said adjustments form no part of the present invention andfurther description thereof is omitted.

The valve 38 has formed therein at its upper end a plurality ofdownwardly converging channels 45 which terminate in the hollow interiorof said valve, while the lower end thereof is provided with a pluralityof downwardly diverging chan nels 46' as shown in Figure 1, whereby itis apparent that any pressure fluid which seeps between the upper end ofsaid valve and said sleeve may escape downwardly through the passages 65to the interior of valve 38- andat the lower end could possibly escapethrough the inclined channels 46 and into the annular cup shaped element51 for withdrawal in the manner hereafter described. This should preventthe building up of any pressure within the interior of the valve orsleeve in excess of that which exists under normal operating conditions.

It must be remembered that the pressure fluid used is under suchpressure that there will naturally be some seepage of fluid between thevalve 38 and sleeve [2. It is contemplated that in the event that thepassages 45 should become clogged fiuid could escape through the outlet53 and into the annular opening 58 formed in the sleeve l2, and it wouldbe a simple matter to provide an outlet in the valve body whichinterconnects the opening 58 and an exhaust channel in said body.

The valve 38 is substantially cylindrical in form and has a plurality ofspaced annular openings 41, 48 and 49 formed therein, whereas the sleevel2 has a plurality of longitudinally spaced annular openings 50, 5|, 52,53, 54 and 55 whose utility will become more apparent in the followingdescription.

From an examination of Figures 1 through 7 it is apparent that each ofthe annular openings 59, 5|, 52, 53 and 54 are adapted for communicationwith the interior of the sleeve l2, and this communication is providedas follows: annular opening 54 also shown in Figure 3 is joined to theinterior of sleeve l2 by a pair of diametrically formed transverse slots60, one of which is shown in Figure 2.

Annular opening 53 as shown in Figures 2 and 4 is joined to the interiorof said sleeve by another pair of diametrically formed transverse slots52, and these slots are positioned degrees from the slots 60.

Annular opening 52 is joined to the interior of sleeve I2 by thediametrically arranged staggered slots 34 as shown in Figures 2 and 5.Annular opening 5| is joined to the interior of sleeve [2 by thediametrically arranged channels 66 as shown in Figures 2 and 6; andannular opening 50 is joined to the interior of said sleeve by the pairof diametrically arranged transverse slots 63 as shown in Figures 2 and7.

Referring now to Figures 3, 4, 5, 6 and 7 it is seen that slots 66 and62 are arranged approximately at right angles to each other, that slots62 and 64 are arranged at right angles to each other, slots 64 and 66are arranged at right angles to each other and that slots 66 and 68 arearranged at an angle of 45 degrees with respect to each other.

It follows further that the slots 60 and 64 are in substantiallongitudinal alignment as are the slots 66 and 62. By this constructionin arranging the outlet passages in staggered relation all the wayaround the interior of the sleeve l2, there is provided a hydraulicallybalanced control valve 38, with the pressure of the fluid in saidpassages being substantially equalized around the surface of said valve.

This promotes for a very well balanced freely movable valve 38 and ithas been found by this construction that the controlled response thereofis substantially immediate. This is particularly desirable in machinetools of this type for the reason that the reproducing operation issubstantially continuous with the best results obtained where you have afreely movable well balanced control valve.

Referring to Figures 1 and 2 as well as Figure 10, the annular sleeveopening 52 is adapted to receive pressure fluid from a suitable remotehydraulic unit which normally includes a fluid storage sump togetherwith a suitable pump for delivering pressure fluid to the tracer.Pressure fluid is provided by a suitable conduit which is adapted toconnect the pressure port 10 which is formed in the body II. Thispressure fluid is conducted through passage 1| in body H whichterminates in the inlet passage 65 which as shown in Figure 5 providesfluid communication to the sleeve opening 52. This pressure fluid isdirected inwardly upon opposite sides of sleeve 2 into the annularopening 48 of valve 38.

In the neutral position of valve 38 corresponding to the tracer 26 beingin contact with the flat surface of the pattern26 this pressure fluid issubstantially locked within the valve opening 48 for the reason that theannular flange 48 completely closes sleeve passages 66; and at the sametime the annular flange 48" of said valve completely covers sleevepassages 62. As shown in Figure 1 of the drawing the aforesaid flanges48' and 48" are in substantially overlapped relation to the respectivesleeve passages 66 and 62 so that there is no flow of pressure fluidoutwardly thru said passages.

Both of the passages 66 and 62 are cylinder passages which are adaptedfor connection to opposite ends of a hydraulic cylinder or cylinders foreffecting either movement of the cylinder relative to a stationarypiston, or movement of a piston with respect to a stationary cylinder,to control feed movements of the cutting tool relative to a work pieceor movement of the work piece relatively to the cutting tool.

Sleeve outlet 66 joins annular sleeve opening 5| which as shown inFigure 6 is adapted to deliver pressure fluid to the body passage 61. Asshown in Figure 10 the outer end of this passage through passage 13establishes fluid communication to the cylinder port 12. A suitableconduit is joined at one end to the port 12 while the other end thereofis joined to one end of a hydraulic cylinder.

The other cylinder port '62 as shown in Figures 1 and 4 joins sleeveopening 53 for delivering fluid through the body passage 63. As shown inFigure 10 this passage is joined to the other cylinder port 14, and thelatter is adapted for connection by a suitable conduit to the oppositeend of the aforementioned hydraulic cylinder.

Thus it is apparent that sleeve opening 66 supplies pressure fluid tocylinder port 12 and that sleeve opening 62 is adapted alternately tosupply pressure fluid to the other cylinder port 14.

In normal operation the pressure fluid is delivered outwardly from theport 12 to one end of the hydraulic cylinder to effect movement of thepiston therein, for example, then the fluid from the opposite side ofsaid piston will be forced outwardly from the other end of suchhydraulic cylinder and will be delivered to the cylinder port 14 andthence to the sleeve opening 53 through the body passage 63.

It will be remembered however, that in the neutral position of the valve38 there will be no flow through either of the sleeve openings 66 or 62for the reason that the same are effectively closed by the valve3848'-48.

Now assuming that there is a lateral thrust delivered to the tracer tip26 by the pattern 26' as they are fed relatively to each other due to arise in the pattern, then as above described this lateral thrust willeffect an immediate upward movement of the spindle 2| so that thepressure fluid which is constantly in valve opening 48 will bleed orflow outwardly through sleeve openings 66, into annular opening 5|,passages 61, 13 and out through cylinder port 12 to cause motion of thepiston within the aforementioned cylinder.

At the same time exhaust fluid from the opposite end of said cylinder isreturned to the tracer through port 14 and passage 63 to sleeve opening53, through sleeve openings 62, and with the valve slightly elevatedfrom the position shown in Figure 1 it is apparent that this exhaustfluid will flow into valve opening 49. Valve opening 49 is an exhaustopening and is at all times in communication with sleeve passages 60 andsleeve opening 54; and as shown in Figure 3 as well as in Figure 10 thisexhaust fluid is delivered to the body passages 6|, 1'! and 16 to thesingle exhaust port 15.

Said exhaust port is joined by a suitable conduit with theaforementioned fluid storage sump so that this exhaust fluid from thecylinder is returned to the hydraulic unit for reuse.

Normally the movement of the control valve 38 is only slight as a matterof thousandths of an inch, usually less than ten thousandths, butsuflicient to bleed or deliver pressure fluid through the sleeve opening66 if the valve 36 is elevated in response to a positive deflection ofthe tracer tip 26 such as where a high point is engaged upon the pattern26.

On the other hand should the tracer tip reach an area which isconsidered slightly inclined inwardly of the pattern 1. e. a low point,then in that event the tracer valve 38 will move downwardly under theaction of the coil spring 4| which transmits its pressure through saidvalve and through spindle 2| so as to constantly urge said tracer tip 26into engagement with the pattern, or in other words maintain the tracertip in engagement with the surface of the pattern continually.

As the present tracer may be described as :a universal type tracer anychange in the surface of the pattern causes such fiow of pressure fluidthrough either of the cylinder ports 12 or 14 as will cause suchmovement of the hydraulic cylinder which will tend to return the tracervalve 38 to the neutral position shown in Figure 1, to

cut off further flow to eitherof the cylinder ports 12 or 14.

Now when the tracer has returned to the neutral position abovedescribed, and thereafter engages a low spot in the surface of thepattern 26, then in that case the valve 38 moves downwardly below theposition shown in Figure 1 so that pressure fluid within valve opening48 will bleed or be delivered outwardly through sleeve passage 62,sleeve opening 53, body passage 63 cylinder port 14, and thus to theopposite end of the hydraulic cylinder in such a manner as to causemovement of the piston therein tending to return the tracer valve 38back to the neutral position shown in Figure 1, to thus cut on furtherflow to said cylinder.

In the manner above described in detail the aforesaid hydraulic cylinderwhen receiving pressure fluid from cylinder port 14 Figure at one end isreturning exhaust fluid from its other end back into the tracer bodythrough cylinder port 12. As shown in Figures 10 and 6 this exhaustfluid passes through body passages 13, El and into sleeve opening 5!,thence through the two oppositely arranged sleeve passages 66. As thetracer valve is below a neutral position the exhaust fluid in thepassages 66 is free to bleed into the exhaust opening 41 in valve 38.

This exhaust fluid is then delivered outwardly through the sleevepassages 68 as shown in Figures 2 and '7, into annular opening 56 andthence through exhaust passage 69 in the tracer body I l through passage76, and outwardly through the exhaust port for return to the hydraulicsump.

It will be noted that both exhaust openings 4'! and 49 of valve 33 areconstantly in communication with the single exhaust port 75 within thetracer body so that it is always possible for exhaust fluid to bereturned to the hydraulic unit either from exhaust opening 41 or exhaustopening 49. Furthermore any seepage of fluid be tween the valve and thesleeve will be also exhausted through the exhaust port 15. Any suchseepage however, is accidental and unintentional, being due to the factthat the valve 38 is slidably fitted within the sleeve l2, and with theoil under pressure there is always bound to be some seepage.

In summary, prmsure fluid is delivered to the tracer at body port ll!Figure 10, and depending upon the positioning of valve 38 will bedelivered outwardly to either of the cylinder ports 72 or 14. Ifpressure fluid is delivered outwardly through port 12 then exhaust fluidreturns through cylinder port 14 for subsequent exhausting outwardlyfrom exhaust port 15. Altern-ately if pressure fluid is deliveredthrough pressure port 14, then in that case exhaust fluid from thecylinder returns to the tracer through the cylinder port 12 andsubsequently out from the tracer through the exhaust port 15.

It will be noted that there is an exhaust port 18 in body II which isactually the low pressure port being joined to a low pressure inducingdevice within the hydraulic unit by means of a suitable conduit. As themethod of obtaining this low pressure forms no part of the presentinvention further description thereof is omitted. The same thing is truewith respect to the hydraulic unit above referred to which is adapted todeliver pressure fluid to the tracer body at port Ill and'receivedexhaust fluid therefrom through the tracer exhaust port I5.

As shown in Figures 1 and 2, exhaust port 18 registers with sleeveopening 55 and the vacuum passage 56 formed therein. As moreparticularly shown in Figure 1 the lower end of passage 56 is shown incommunication with the seepage collector 51 which is positioned withinthe lower portion of sleeve [2 and is adapted to collect any fluid whichmay seep downwardly either from valve passages 66' or from between valve38 and the interior of said sleeve.

Before this seepage fluid overflows Collector 57 it will be withdrawnthrough the vacuum passage 56 and therefore such seepage will not rundown the outer surface of the tracer spindle.

As shown in Figure 8 all of the sleeve passages 6-9, 62, 64, 66 and =63are of the generally eliptical shape indicated.

While the tracer arm 24 is shown eccentric relative to spindle 2| it iscontemplated that said arm could just as Well be coaxial therewith ifdesired.

It will be understood that while in applicant's preferred embodiment ofthe invention the transverse slots 60, 62, B4, 66 and 68 are arranged instaggered relation around the sleeve 12, it is contemplated that anyother convenient arrangement may be employed. Said slots could bearranged in vertical rows or in any other convenient position ifdesired.

The important thing is that each of the pairs of said slots are opposedto each other bein oppositely arranged and formed within the sleeve 12.The valve which is movable within said sleeve is balanced by the factthat in each individual groove the corresponding inlet slots 60, B2. 54,66 and 68 are exactly opposed.

The respective inlet passages '65, 67, 63, 6| and 69 are normallyarranged intermediate the outer ends of each pair of opposed inletslots. Thus the fluid flow is split up and either enters or leaves thevalve and sleeve upon opposite sides thereof; and by this constructioneach pair of said inlet slots or ports is in hydraulic balance.

Thus at all times the pressure is equalized upon the valve and upon allportions thereof.

Having described my invention reference should now be had to the claimswhich follow for determining the scope thereof.

I claim:

1. In a hydraulic tracer having a housin and an axially movable patternresponsive spindle therein, said spindle having a transverse slot formedtherein, a stabilizer pin loosely projected through said slot, andeccentric trunnion shafts at the opposite ends of said pin pivotallymounted within said housing.

2. In a hydraulic tracer having a housing and an axially movable patternresponsive spindle therein, said spindle having a transverse slot formedtherethrough, and a stabilizer pin loosely projected through said slotwith its ends eccentrically arranged with respect to the axis of saidpin, and with said ends pivotally mounted within said housing.

3. In a hydraulic tracer having a housing and an axially movable patternresponsive spindle therein, a transverse adaptor at the lower end ofsaid spindle, a tracer arm depending from said adaptor with itslongitudinal axis offset withrespect to the spindle axis, a transversetracer tip with its axis at right angles to the spindle axis adjustablypositioned within said tracer arm, and means to secure said tracer tipin adjusted position.

4. In a hydraulic tracer having a hOllSll'lg and an axially movablepattern responsive spindle therein, said spindle having a transverseslot formed therein, a stabilizer pin loosely projected through saidslot, eccentric trunnion shafts at the opposite ends of said pinpivotally mounted Within said housing, a hollow pressure fluid conductimsleeve having a plurality of longitudinally spaced annular fluidopenings at its outer surface, there being a pair of oppositely arrangedtransverse channels formed in said sleeve connecting each of saidopenings with the interior of said sleeve, pairs of channels beingarranged in staggered relation around said sleeve, a fluid control valveslidably positioned Within said sleeve and bearing upon said spindle,there being a plurality of fluid passages formed in said housing eachrespectively joining one of said annular i'iuid openings and beingarranged intermediate the outer ends of each pair of opposed channels tothereby equalize the fluid pressure efiect throughout the entireexterior surface of said valve.

GALE HUMES.

10 REFERENCES CITED The following references are of record in the fileof this patent:

UNITED STATES PATENTS

